Browsing by Subject "phytosterols"

Hexanal is a highly volatile liquid that can prolong the shelf life of fruits and vegetables (Paliyath and Subramanian 2008). Previously, Lehtonen et al. (2020) introduced a freeze-dried active packaging material which was continuously releasing hexanal through the naturally occurring lipid oxidation reactions of sunflower oil. In this study, nine different sunflower oil-based matrices were characterized at different stages of their preparation process. They contained crystallization modifiers (acylglycerols, phytosterols, or their blend), coating materials (gum Arabic and maltodextrin), and were produced by spray-drying of an emulsion. The crystallization modifiers in the matrix may enable the control over the start of the reaction for hexanal release. The emulsions with crystallization modifiers were significantly unstable, their viscosity increased with an increasing proportion of gum Arabic, and they contained crystalline regions from the first day of preparation. All tested emulsions formed a white powder after spray drying and the powder particle sizes were characterized. The differential scanning calorimetry (DSC) did not reveal any melting point of the lipid phase in majority of the powder samples. However, the DSC results showed that the melting temperatures of corresponding oleogels with acylglycerols and acylglycerol/phytosterol blend were 64 and 56.6 °C, respectively. In this thesis, emulsions containing acylglycerols and/or phytosterols were characterized and shown to be suitable for the encapsulation by the spray drying technique. Further studies focusing on the hexanal release from the matrix need to be performed since no hexanal release was detected from the powder samples.